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The contradiction between water demand and water supply in the Yellow River Delta restricts the corn yield in the region. It is of great significance to formulate reasonable irrigation strategies to alleviate regional water use and improve corn yield. Based on typical hydrological years (wet year, normal year, and dry year), this study used the cou...
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... irrigation treatments (I1, I2, and I3) were tested according to the maize growth status, with total irrigation of 186.3 mm under I1 total irrigation of 130 mm under I2, and rainfed conditions under I3, with three replicates for each treatment. The maize growth period was divided into the seedling stage, jointing stage, tasseling stage, and filling stage, and the irrigation measures for the treatments in 2019-2021 are shown in Table 1. The properties of the soil in the 0-80 cm soil layer in the test area are shown in Table 2. ...Citations
... The conventional approach to irrigation scheduling relies on analyzing average multiyear meteorological data, often derived from long-term rainfall records or a representative hydrological year [10,11]. While the conventional approach is practical and convenient, it tends to overlook the influence of random rainfall patterns. ...
The North China Plain plays a pivotal role in China’s crop production, contributing to 30% of the maize yield. Nevertheless, summer maize in this region faces challenges due to climatic constraints characterized by concurrent high temperatures and rainfall during the growing season, resulting in a relatively high evapotranspiration rate. In this study, we explored eight soil moisture-based threshold irrigation strategies, consisting of two upper limits and four lower limits, along with a rainfed mode (E). The upper and lower irrigation limits are expressed as a percentage of the field’s water-holding capacity (sfc). For the four full irrigation modes (A1, A2, A3, A4), the lower limits were set at 0.6 sfc, 0.6 sfc, 0.5 sfc, and 0.5 sfc, respectively. The upper limits were defined at two levels: 0.8 sfc for A1 and A2 and sfc for A3 and A4. Similarly, for the four deficit irrigation modes (B1, B2, B3, B4), the lower limits were established at 0.4 sfc, 0.4 sfc, 0.3 sfc, and 0.3 sfc, respectively, with the upper limits set at two levels: 0.8 sfc for B1 and B2 and the full sfc for B3 and B4. To investigate the impact of rainfall and potential evapotranspiration on these irrigation modes under long-term fluctuations, we employed a stochastic framework that probabilistically linked rainfall events and irrigation applications. The Monte Carlo method was employed to simulate a long-term series (4000a) of rainfall parameters and evapotranspiration using 62 years of meteorological data from the Xinxiang region, situated in the southern part of the North China Plain. Results showed that the relative yield and net irrigation water requirement of summer maize decreased with decreasing irrigation lower limits. Additionally, the interannual variation of rainfall parameters and evapotranspiration during the growing season were remarkable, which led to the lowest relative yield of the rainfed mode (E) aligned with a larger interannual difference. According to the simulation results, mode A4 (irrigation lower limit equals 0.5 sfc, irrigation upper limit equals 0.8 sfc) could be adopted for adequate water resources. Conversely, mode B2 is more suitable for a lack of water resources.
... In the coming decades, agriculture will cope with food security for the increasing world population without affecting environmental security. It is very influential in formulating suitable fertilization strategies to alleviate fertilizer use and improve crop yields [29]. ...
... with food security for the increasing world population without affecting environmental security. It is very influential in formulating suitable fertilization strategies to alleviate fertilizer use and improve crop yields [29]. ...
The Yellow River Delta is an important grain production base in China, and it is a typical Yellow River irrigated area. Chemical fertilizer overuse has seriously affected grain production safety, and understanding the fertilizer application situation is useful for scientific agronomy management. In this study, we collected the data of the N, P, K fertilizers for crop cultivation in Donging City from 2011 to 2020, and we collected 185 investigating questionnaires to gather information on the fertilizer application rate for small farmers. The results showed that the amount of total fertilizer used has decreased from the year 2015, but the macro element fertilizer rate for crop cultivation exceeded the recommended dosage. The application of compound fertilizer increased during the investigated 10 years, and its proportion in 2020 was 1.65 times higher than in 2011. For obtaining an ideal grain yield, the N and P2O5 had relative reduction rates of 67.8% and 69.6% for wheat planting. Furthermore, the relative reduction rates of N, P2O5, and K2O were 25.9%, 69.6%, and 59.7%, respectively, for maize cultivation when compared to the recommended dosage. During wheat growth, the potassium fertilizer was needed to increase the dosage, although the K element content in the soil was high. Furthermore, the medium and trace elements are all important nutrients for improving crop yield and quality which need to be studied. More scientific measurements should be conducted to match chemical fertilizer reduction to constructing healthy and sustainable agriculture in the Yellow River irrigated area.
... Elaborating irrigation scheduling merely on the basis of empirical data from field research is time consuming, costly, and hard to extrapolate to other locations and climates. Crop growth simulation models (also called crop models) alternatively allow systematic characterization of crop water use, growth, development and yield in terms of various environmental conditions and management strategies, and have been widely used to identify irrigation management scenarios to effectively maintain high crop yield under conditions of limiting water supply (Farahani et al., 2009;García-Vila et al., 2009;Kisekka et al., 2017;Umesh et al., 2022;Shan et al., 2023). ...
Determination of relative root-zone water depletion (RRWD) thresholds to trigger irrigation is crucial to create optimal irrigation schedules targeting maximum yield and/or water productivity with limited water supply for a crop. In this study, a numerical procedure to determine RRWD thresholds was developed through coupling AquaCrop software with genetic-simplex algorithms. Using a two-year field lysimetric experiment for winter wheat conducted in the North China Plain (NCP), AquaCrop adequately simulated canopy cover, final above-ground biomass, grain yield, seasonal evapotranspiration, and soil water storage, with the normalized root mean squared error (NRMSE) smaller than 15 % and determination coefficient (R 2) larger than 0.84. The global optimum range of RRWD thresholds was preliminarily determined using the genetic algorithm, and subsequently final RRWD thresholds were optimized by fine tuning using the simplex algorithm. The RRWD threshold combinations (composed of the RRWD thresholds to trigger different sequential irrigation events) for varying number of irrigation events (i.e.1-4) were optimized based on 39 years of historical meteorological data, and the effects of climate change on the optimal crop yield (Y a, opt), water productivity (WP opt), and the combinations of optimized RRWD threshold (RRWD opt) were investigated. The results indicated that both Y a, opt and WP opt generally increased with time showing a tendency of gradually elevated annual CO 2 concentration and seasonal average effective temperature. Irrespective of the number of irrigation events during the winter wheat growing season, the differences of RRWD opt for different combinations of irrigation sequence and event in the same kind of hydrological year were relatively small, with a coefficient of variation consistently less than 23 % and a mean of 8 %. When combinations of mean RRWD opt were applied into AquaCrop to trigger irrigation for winter wheat in various hydrological years, the simulated yield (Y a, sim) and water productivity (WP sim) under 1-4 irrigation events were found to be comparable to their respective optimums (Y a, opt and WP opt), with all the values of Y a, sim (WP sim) falling in the range of 92 %Y a, opt (90 %WP opt). Therefore, the mean RRWD opt should be helpful to formulate rational irrigation management strategies of winter wheat under changing climatic conditions in the NCP.
